My greatest lesson in life has been learning how much we actually don’t know. But I’ve taken matters into my own hands by writing books on promoting plant growth and protecting crops, in order to share my knowledge with others, along with a vision for a grassroots strategy that can bypass the established power structure. A bottom-up approach to transformation: ideas conveyed in a way that appeals to a broader audience.

I’ve given up on my dream of bringing about change through politics. Although the leading suppliers of biological pesticides loudly proclaim in the media and among policymakers that they are shaping the transition to sustainability, my books show that their actual toolkit is paperthin. They claim to be in charge, but fail to offer the full range of possible solutions needed to keep diseases, pests, and weeds below the economic damage threshold that a grower requires.

More than ever, I feel called upon to shed light on what is going on – even if it means rubbing a few people the wrong way here and there – so that we can awaken from our slumber and develop more preventive solutions. My books contain provocative and disturbing findings about measures taken that favor vested interests at the expense of broad transparency in the agricultural sector – I’m lifting a corner of the veil, so to speak – so that we can understand what we’re up against. Yet, my findings are rarely cited in professional circles. But the fact that my data on biological pesticides is hidden behind a paywall by a former government agency that provides agricultural extension services is actually a very positive sign!

Whenever I challenged the prevailing system, I encountered people who make decisions that benefit themselves at the expense of others. However, to spread the truth, we need a more strategic and revolutionary approach that cannot be corrupted by powerful individuals who have a stake in the current situation. Through my search for the truth, I’ve learned an important lesson about ego, power, and control, and I’ve seen how ‘truths’ are manipulated at the highest levels. In hindsight, the warnings form many well-meaning people were justified. But if I had the change to do it all over again, I would do exactly the same thing.

Theo Grent, coordinator biological products – Berlin, July 2026

Products containing bacteria and/or fungi

Theo Grent, coordinator of biological agents, states that the microorganisms* listed and their corresponding brand names may be offered, recommended, and used in horticulture. These products are intended to restore microbiological biodiversity in soils, growing media, and the root zone. Whether in the Netherlands a product must be authorized under the Crop Protection Products and Biocides Act (Wgb’07) is ultimately determined by the NVWA, following consultation with the Ctgb. Whether a product name can be included in Part 2 (crop protection product) or Part 1 (biostimulant) of the so-called biological input list is ultimately determined by Skal Biocontrole, following consultation with FiBL.

* Organisms selected in laboratories and cultivated in biotechnology facilities.

Reference work (www.kelbo.nl) – Year – Coordinator biological agents

• Plant protection new style – 2010 – Market overviews at the request of producers
• The regenerative approach – 2019 – Market overviews at the request of growers
• Beyond organic – 2021 – Market overviews at the request of bio-vegan
• The agroecological approach – 2026 – Market overviews at the request of bio-sector

Contact your horticultural supplier, consult reference works, and verify the data – whether or
not for a fee – with your advisor, so that you, too, can offer, recommend, and use (as a grower)
the products mentioned in conventional, agroecological, and organic growing methods.

*The Floribusiness / Hortipoint editorial team accepts no responsibility for the content of this article. Before using any product, always verify that it is authorised for use in your crop.